A physiologically based pharmacokinetic (PBPK) model for inhaled trichloroethylene (TCE) was developed for B6C3F1 mice. Submodels described four P450-mediated metabolites of TCE, which included ...chloral hydrate (CH), free and glucuronide-bound trichloroethanol (TCOH-f and TCOH-b), trichloroacetic acid (TCA), and dichloroacetic acid (DCA). Inhalation time course studies were carried out for calibration of the model by exposing mice to TCE vapor concentrations of either 100 or 600 ppm for 4 h. At several time points, mice were euthanized and blood, liver, kidney, lung, and fat were collected and analyzed for TCE and its oxidative metabolites. Peak blood TCE concentrations were 0.86 and 7.32 microgram/mL, respectively, in mice exposed to 100 and 600 ppm TCE. The model overpredicted the mixed venous blood and tissue concentrations of TCE for mice of both exposure groups. Fractional absorption of inhaled TCE was proposed to explain the discrepancy between the model predictions and the TCE blood time course data. When fractional absorption (53%) of inhaled TCE was incorporated into the model, a comprehensive description of the uptake, distribution, and clearance of TCE in the blood was obtained. Fractional uptake of inhaled TCE was further verified by collecting TCE in exhaled breath following a 4-h constant concentration exposure to TCE and validation was provided by testing the model against TCE blood concentrations from an independent data set. The submodels adequately simulated the distribution and clearance kinetics of CH and TCOH-f in blood and the lungs, TCOH-b in the blood, and TCA and DCA, which were respectively detected for up to 43 and 14 h postexposure in blood and livers of mice exposed to 600 ppm TCE. This is the first extensive tissue time course study of the major metabolites of TCE following an inhalation exposure to TCE and the PBPK model predictions were in good general agreement with the observed kinetics of the oxidative metabolites formed in mice exposed to TCE concentrations of 100 and 600 ppm.
First Images of Asteroid 243 Ida Belton, M. J. S.; Chapman, C. R.; Veverka, J. ...
Science (American Association for the Advancement of Science),
09/1994, Letnik:
265, Številka:
5178
Journal Article
Recenzirano
The first images of the asteroid 243 Ida from Galileo show an irregular object measuring 56 kilometers by 24 kilometers by 21 kilometers. Its surface is rich in geologic features, including systems ...of grooves, blocks, chutes, albedo features, crater chains, and a full range of crater morphologies. The largest blocks may be distributed nonuniformly across the surface; lineaments and dark-floored craters also have preferential locations. Ida is interpreted to have a substantial regolith. The high crater density and size-frequency distribution (-3 differential power-law index) indicate a surface in equilibrium with saturated cratering. A minimum model crater age for Ida-and therefore for the Koronis family to which Ida belongs-is estimated at 1 billion years, older than expected.
Objective:
To descirbe smiling and euphoria induced by deep brain stimulation (DBS).
Background and Significance:
The brain systems inducing emotional experiences and displays are not entirely known, ...but the ventral striatum including the nucleus accumbens have been posited to play a critical role in mediating emotions with positive valence. DBS has been successfully employed for the treatment of movement disorders, and most recently obsessive compulsive disorder (OCD). The purpose of this report is to describe the emotional changes associated with stimulation of the ventral striatum.
Methods:
A single patient with intractable OCD had electrode arrays placed in the right and left anterior limbs of the internal capsule and region of the nucleus accumbens. Changes in facial movement during stimulation were quantified by video recording. Ten video segments, time locked to the onset of stimulation, were digitized and changes in pixel intensity that occurred over both sides of the lower face, on a frame by frame basis, following stimulation onset were computed. These summed changes in pixel intensity represented the dependent variable of "entropy" and directly corresponded to changes in light reflectance that occur during facial movement.
Results:
During stimulation on both the right and left side, the patient consistently developed a half smile on the side of the face contralateral to the stimulating electrode, and also became euphoric. The effect ceased when DBS was discontinued.
Conclusions:
DBS in the region of the nucleus accumbens produced smile and euphoria suggesting that alterations in the ventral striatum may result in emotional experience and displays. We hypothesize the existence of a limbic-motor network responsible for such changes. This observation suggests that DBS may be useful as a therapy for mood disorders.
The effects of temperature on insect life history were studied for two whitefly hosts (Homoptera: Aleyrodidae), the silverleaf whitefly, Bemisia argentifolii Bellows & Perring, and the greenhouse ...whitefly, Trialeurodes vaporariorum (Westwood), as well as the parasitoid, Eretmocerus eremicus Rose & Zolnerowich (Hymenoptera: Aphelinidae) attacking both hosts. Mean egg numbers as a function of time were fitted to models for age-specific oviposition for each whitefly. For B. argentifolii, numbers of eggs laid increased with time at 15, 21, and 24°C. At 28 and 32°C, the curve declined after 6 d, although the model fit was poor. The model did not fit the oviposition data at 32°C. Maximal oviposition rate occurred at 24°C (12 eggs per 48-h period), and the model was almost linear. For T. vaporariorum, the model closely fit mean eggs laid, with highest rates of ≈12 eggs per 48 h at 21 and 24°C. Numbers of whitefly eggs as a function of time and temperature were described by a three-dimensional surface model that was also used to estimate temperature thresholds for oviposition (12.5°C for B. argentifolii and 10.9°C for T. vaporariorum). Increasing temperatures produced decreased preoviposition periods in B. argentifolii, whereas temperature extremes resulted in longer periods for T. vaporariorum. Development times from egg to adult, percentage mortality, and estimated degree-days for development were measured at 15, 21, 24, 28, and 32°C for both whiteflies, and for E. eremicus reared on both hosts. Development rate was higher for B. argentifolii than T. vaporariorum at 24 and 28°C. Development of E. eremicus was faster using B. argentifolii as hosts than T. vaporariorum at 24, 28, and 32°C. By extrapolation of development rates, lower developmental thresholds (°C) were estimated as follows: T. vaporariorum, 2.92; B. argentifolii, 10.32; E. eremicus on T. vaporariorum, 5.44; and E. eremicus on B. argentifolii, 8.7. Mean degree-day requirements for egg to adult development were calculated for T. vaporariorum, 483.4; B. argentifolii, 319.7; E. eremicus on T. vaporariorum, 417.3; and, E. eremicus on B. argentifolii, 314.4. Percentage mortality also was significantly affected by temperature in both species of whitefly. For T. vaporariorum, higher temperatures caused higher levels of mortality, with almost 98% killed at 32°C. The reverse occurred in B. argentifolii, where highest levels of mortality were found at the lowest temperatures. Mortality patterns in E. eremicus reflected those of the host: increasing with temperature on T. vaporariorum, while decreasing on B. argentifolii. The life history of E. eremicus was profoundly affected by that of its host.
This article presents the basis for, and the research on, emotionally focused couples therapy (EFT), now recognized as one of the most researched and most effective approaches to changing distressed ...marital relationships. Drawing on attachment theory and the research on interactional patterns in distressed relationships, we describe the theoretical context of EFT. We then outline the nature of the clinical interventions used in EFT and the steps hypothesized to be crucial to couple change. The central role of accessing and working with emotional issues in the relationship context is highlighted. Following this presentation, we review both the outcome and process research on EFT and present meta‐anarytic data from randomized clinical trials to substantiate the clinical impact of EFT on couple adjustment. Finally, the empirical and clinical challenges facing EFT are summarized.
The portions of the electronic record that were reviewed included: (1) history; (2) physical exam; (3) diagnostic testing including urine human chorionic gonadotropin (hCG), and gonorrhea and ...chlamydia cultures; (4) antibiotic treatment; and (5) discharge instructions. The statistically significant increase in appropriate drug dosing when evidence based computerized physician order entry (CPOE) order sets are available, as compared to free-form computer order entry in the historic controls suggests that the CDS that CPOE provides has the potential to improve patient care.
Objectives. A technique for terminating refractory ventricular fibrillation is described.
Background. Refractory ventricular fibrillation can occur in up to 0.1% of electrophysiologic studies. Animal ...studies have shown that rapid sequential shocks may reduce ventricular fibrillation threshold.
Methods. Five patients of 2,990 consecutive patients in a 3-year period experienced refractory ventricular fibrillation during 5,450 routine electrophysiologic studies. Multiple shocks were delivered by means of a single defibrillator. Double sequential shocks were delivered externally 0.5 to 4.5 s apart by means of two defibrillators with separate pairs of electrodes.
Results. In all patients, standard defibrillation was unsuccessful, but all were successfully resuscitated using the double sequential shocks.
Conclusions. This report stresses the importance of an additional defibrillator being readily available during electrophysiologic testing. This technique of rapid, double sequential external shocks may have general applicability, providing a simple and potentially lifesaving approach to refractory ventricular fibrillation.
Moral injury (MI) refers to the persisting distress which may occur following exposure to potentially morally injurious events (PMIEs). The COVID-19 pandemic has drawn attention to MI in healthcare ...workers, who have been found to experience more frequent PMIEs in their day-to-day work than those in other occupational groups such as the military. These events may occur on an individual, team, organizational or system level and have been associated with increased clinician burnout and distress, and poor psychological wellbeing. This paper focuses on healthcare workers' experiences of MI, including potential causes and ways to reduce them. There are myriad challenges that influence the development of MI, such as chronic understaffing and the pressure to treat high numbers of patients with limited resources. There are also multiple impacts of MI: at the individual-level, MI can lead to increased staff absences and understaffing, and prolonged patient contact with limited decision-making power. COVID-19 exacerbated such impacts, with a lack of organizational support during a time of increased patient mortality, and uncertainty and heightened pressure on the clinical frontline associated with scarce resources and understaffing. Potential methods for reduction of MI in healthcare workers include pre-exposure mitigation, such as fostering work environments which treat PMIEs in the same way as other occupational hazards and post-exposure mitigation, such as facilitating healthcare workers to process their experiences of PMIEs in peer support groups or with spiritual advisors and, if MI is associated with mental ill-health, talking therapies using trauma-focused and compassion-oriented frameworks. Keywords: moral injury, healthcare workers, causes, effects, mitigation, pandemic, prevention, treatment
A single comprehensive reference for nursing leaders, leadership organizations, nursing clinicians, and educators, Nursing Leadership is the only compendium of nursing terminology in existence. ...Written by eminent nursing professionals, it provides descriptions of prominent individuals in nursing, information regarding nine leadership-related topics, and current trends in nurse leadership. This second edition has been expanded to encompass 80 new entries and revisions or updates to all original entries. It provides an extensive overview of current leadership issues including theories, characteristics, and skills required of nurse leaders in today's complex health care system. Highly respected contributors include Claire Fagan, Beverly Malone (NLN CEO), Polly Bednash (AACN CEO), Patricia Benner, and many others. For ease of use this new edition contains both alphabetic and thematic indexes, extensive cross- referencing, and print and web references for each entry. The new edition features: * Thematic list of entries in addition to alphabetic index * An extensive overview on salient nursing leadership issues, themes, characteristics, and current and future developments * A "legacies" section on nursing luminaries throughout history * Over 80 new entries and updates and revisions of original entries * Extensive cross-referencing and print and web resources for each entry
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